Right bottom of your start bar, audio speakers thing should have program specific sliders (At least if you use vista or 7) try checking if the warband slider is down. If not you should check the control panel at output to see if the you didn't lower that slider on accident using a keybind.

Yesterday i had some problems as well. It suddently turned off my sound ingame (E.Y.E.) and in ts. Had to change USB ports, restart ts and everyone sad i had an ugly voice or so. Dont know what it was. Had an ts update today and nothing happend so far.